High-speed reclosing circuit breaker



1952 R. o. BONINE ET AL 2,619,523

HIGH-SPEED RECLOSING CIRCUIT BREAKER Filed April 7, 1951 2 SHEETS-SHEET 1 WITNESSES:

Ralph O. Bonine 8 WW Samuel H. Boden.

BY QJ 7 ATTORN INVENTORS Nov. 25, 1952 R Q BQNINE ETAL 2,619,523

HIGH-SPEED RECLOSING CIRCUIT BREAKER Filed April '7, 1951 2 SHEETSSHEET 2 WITNESSES:

/f Ralph O. Bonine a M S omuel H. Boden W Ci 2) 7 ATTORNE INVENTORS Patented Nov. 25, 1952 HIGH-SPEED RECLOSING- CIRCUIT BREAKER Ralph 0. Bonine, Pittsburgh, and Samuel H.

Boden, Turtle Creek, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa.,. a corporation of Pennsylvania Application April 7, 1951, Serial No. 219,854

Claims.

This invention relates to circuit breakers and more particularly to circuit breakers of the type which are adapted to be quickly reclosed upon the initial opening thereof by fault conditions in the circuit.

High speed operation of circuit breakers is becoming increasingly important, and circuit breakers are now desired embodying operating mechanisms which are capable of quickly reversing the switching movement of the contacts in order to provide high speed opening of the contacts, and quick automatic reclosing of the contacts immediately after interruption of a fault circuit. Automatic reclosing time can be materially reduced by quickly reversing the opening movement of the breaker to reclose the contacts immediately after interruption of the circuit, particularly if the reclosing movement i initiated before the breaker reaches full open position. In large power operated circuit breakers, the closing means is usually energized by means of relays in a control circuit, consequently the energizatio-n of the closing means is delayed for the time interval required for the relays to pick up and close the contacts over which the closing means is energized.

An object of the invention is to reduce the reclosing time of an automatic reclosing circuit breaker.

Another object of the invention is to provide a circuit breaker embodying means for quickly effecting energization of the breaker closing means following an initial opening operation.

Another object of the invention is to provide acircuit breaker embodying trip-free and nontrip-free tripping means with means for quickly effecting energizaticn of the breaker closin means following a non-trip-free tripping operation.

The novel features that are considered characteristic of the invention are set forth in particular in the appended claims. The structure and operation of the. invention, together with additional objects and advantages thereof, will be best understood from the following detailed description thereof when read in conjunction with the accompanying drawings.

In said drawings:

Fig. 1 is an elevational view, partly in section, of the operating mechanism for the circuit breaker, the circuit breaker being shown schematically.

Fig. 2 is a schematic view showing the control circuit for the circuit breaker.

The circuit breaker operating mechanism may be of any suitable construction but is preferably similar in construction to the mechanism disclosed in Patent 2,422,562, issued June 17, 1947 to Henry L. Peck and assigned to the assignee of the present invention.

Referring to Fig. 1, the circuit breaker comprises a main casting 9 which is formed to provide an operating cylinder having a plate I3 which forms a closure for the upper end of the operating cylinder and also acts as a support for the several parts of the operating mechanism. An operating piston I5 is reciprocably movable in the cylinder and together with the cylinder comprises a fluid motor for operating the circuit breaker. The lower end of the cylinder H is closed by means of a closure member I! secured thereto in any suitable manner.

Mounted on the plate I3 is a lever mechanism of the trip-free type comprising a closing lever 2| pivoted at its right-hand end on a fixed pivot 2'1 and a breaker lever 23 having its left-hand end pivoted by means of a pivot pin 33 to the free end of the closing lever 2|. The closing lever 2| comprises a pair of spaced outer levers (only one being shown) having their right-hand ends pivoted on aligned pivot pins 21 (only one being shown), carried by spaced vertical plates 29 (only one being shown) mounted on the plate l3. The breaker lever 23 consists of a pair of spaced inner levers (only one being shown) pivoted at their left-hand ends on the pivot pin 33 carried by and connecting the free ends of the closing levers 2|. The right-hand end of the breaker lever 23 carries a latch roller 35 mounted on a pin carried by and connecting the free ends of the inner levers which form the breaker lever 23.

The circuit breaker may be of any suitable construction either of the liquid or air break type and is shown schematically in Fig. l as comprising stationary -contac-ts 31 and a spring biased movable bridging contact member 4|. The movable bridging contact member 4| is carried by a rod 46 which is connected to the mid-portion of the breaker lever 23 through the agency of a pivoted lever 41 and an operating rod 49, the lower end of the operating rod being pivotally connected to the breaker lever by a pivot pin 5|. The circuit breaker is biased to the open position by means of an accelerating spring 53.

The breaker lever 23 is biased upwardly by the opening bias of the circuit breaker and is releasably held by means of a trip-free latch pivoted on a pivot pin 51 supported in the vertical plates 29 and engaging the latch roller 35 on the free end of the breaker lever. The closing lever 2| is connected to the operating piston |5 by means of connecting links 58 and by a piston rod extending into the cylinder I. The free end of the closing lever 2| is releasably held in closed position, as shown in full lines in Fig. 1 by a non-trip-free latch 59 pivoted on a pivot pin 6| supported by a pair of spaced plates 62 (only one being shown). The latch 59 engages a roller 63 on the pin 33 at the free end of the closing lever. The closin lever 2| is biased in a clockwise direction by means of a pair of retrieving springs (only one being shown) disposed between the outer levers and the plate I3.

When the trip-free latch 55 is actuated to release the free end of the breaker lever 23, the breaker is moved to the open circuit position at high speed by the accelerating spring 53 free of any restraint by the closing means. The opening movement of the circuit breaker causes the breaker lever 23 to rotate counterclockwise about the pivot pin 33 which is held down by the nontrip-free latch 59. The breaker lever 23 is provided with a projection 61 which, during the opening movement, engages and actuates the non-tripfree latch 59 to release the free end of the closing lever 2| whereupon the retrieving springs rotate the closing lever 2| clockwise about its fixed pivot 21. This movement of the closing lever 2| efiects clockwise rotation of the breaker lever 23 about the pivot pin 5| to thereby return the trip-free latch roller 35 to latching engagement with the latch 55. At this point the breaker is again operatively connected to the closing lever 2| and therethrough to the piston I5.

The circuit breaker is closed by admitting a charge of compressed fluid to the upper end of the cylinder II to move the piston I5 downwardly. This rotates the levers 2| and 23 together in a counterclockwise direction about the fixed pivot 2! to the closed position. When the levers reach the closed position, the non-trip-free latch 59 reengages the roller 63 to latch the levers in the closed position.

The circuit breaker may also be tripped open by operation of the non-trip-free latch 59 in which case the circuit breaker is moved to the open position rotating the two levers 2| and 23 clockwise about the fixed pivot 21 to the open position. In this instance the circuit breaker remains operatively connected to the piston 55 so that the circuit breaker can be reclosed instantly from an intermediate open position after the arc is extinguished and before the contacts reach full open position. This high-speed reclosing operation is initiated by admitting fluid under pressure to the upper end of the cylinder at an intermediate point in the opening movement of the breaker so as to initiate the reclosing movement before the breaker reaches full open position.

Fluid pressure for movin the operating piston I5 downwardly to close as to reclose the breaker, is supplied from an auxiliary reservoir 7| which is supplied from a main storage tank (not shown). The supply of fluid pressure to the upper end of the operating cylinder II is controlled by an inlet valve mechanism shown schematically at F3. The valve mechanism I3 is biased to a closed position in which the valve shuts off the supply of fluid pressure to the operating cylinder and at the same time connects the upper end of the operating cylinder to atmosphere. An electromagnet is provided to actuate the valve to the open position to admit fluid pressure to the operating cylinder to close or reclose the breaker. The valve mechanism may be of any suitable construction but is preferably similar in construction to the inlet valve mechanism disclosed in Patent No. 2,408,199, issued September 24, 1946 to J. M. Cumming and R. C. Cunningham, and assigned to the assignee of the present invention.

The trip-free latch 55 is biased by means of a spring 7'! to latching position and is actuated to released position by a trippin electromagnet I9 mounted on the plate I3 beneath the latch 55.

I The tripping electromagnet 19 comprises a movable armature 8| and an energizing winding 83. The armature 8| is biased to unattracted position by a spring and carries a rod 81 for engaging a projection 89 of the latch 55 to actuate the latch and effect release of the breaker lever 23 upon energization of the tripping magnet 19.

Similarly the non-trip-free latch 59 is biased to latching position by a spring 99 and is operated to unlatching position by a tripping electromagnet 9| mounted on the plate I3 below the non-tripfree latch 59. The tripping electromagnet comprises a movable armature 93 and an energizing winding 95. A spring 91 biases the armature 93 to unattracted position, and a rod 99 attached to the armature 93 engages a projection IEJI on the latch 59 upon energization of the tripping magnet 9| to actuate the latch 59 and efiect release of the levers 2| and 23. The latching means 55 and 59 are preferably of the type disclosed in the aforementioned Patent No. 2,408,199.

The circuit breaker is adapted to be automatically tripped open in response to predetermined abnormal conditions in the circuit controlled by the breaker, that is, in response to fault conditions, such as overload currents or short-circuit currents. Automatic tripping of the breaker in response to such fault conditions is initiated by the operation of a fault responsive relay indicated generally at I93 (Fig. 2) which, when operated, completes an energizing circuit for the tripping means. Electrical energy for energizing the tripping electromagnets is supplied from auxiliary supply lines I05 and I97.

Automatic trip selecting means is provided to efiect tripping of the breaker by the non-tripfree tripping means or the trip-free tripping means according to the energized condition of the closing means. when the closing means is deenergized, the tripping will be eiiected by the non-trip-free tripping means and tripping will be effected by the trip-free tripping means if the fault condition occurs when the closing means is energized, that is, when there is fluid under pressure in the cylinder I about the piston I5.

The trip selecting means comprises an automatic selecting switch I09 which is operative in accordance with the condition of the closing means to automatically determine Which of the two tripping magnets 79 or 9| will be energized in response to the fault condition. The trip selector switch comprises a pair of back contacts I I I and a pair of front contacts 1 I3 which are selectively closed by a bridging contact I I5. Referring to Fig. '2' of the drawings, one side of the windings 83 and 55 is connected by a conductor II! to the auxiliary supply line Hi5. An auxiliary switch H9 operated by the circuit breaker is connected in series relation in the conductor Ill, and this switch 9 is closed when the breaker is closed and opened when the breaker is opened. The other side of the winding 95 of the non-trip-free If a fault condition occurs tripping means is connected by a conductor I23 to one of the back contacts III of the selector switch I09. The other back contact I I I and the corresponding front contact 3 are connected by a common conductor I through normally open contacts I21 of the fault relay to the supply line I01. The other side of the trip-free coil 83 is connected by a conductor I29 to the other front contact N3 of the selector switch I09 and to the supply line I01 through the contacts of a manual opening switch I33. Closure of the switch I33 energizes only the trip-free tripping magnet 19 so that the breaker is always tripped free of the closing means when tripping is initiated by the manual switch I33.

The selector switch I09 is controlled by a small piston I responsive to the pressure in the operating cylinder II. The piston I35 is connected to the bridging contact II 5 of the selector switch and is reciprocably movable in a small cylinder I31 mounted on the plate I3 over the operating cylinder II. The lower end of the cylinder I31 communicates with the interior of the cylinder II by means of a passage I39 formed in the portion I3 of the casting 9. A spring I4| biases the piston I35 downwardly to bias the bridging contact II5 into engagement with the back contacts I II of the selector switch. The selector switch occupies this-position at all times when there is no fluid pressure in the operating cylinder II, that is, when the closing means is in deenerg-iz'ed condition.

In the normal position, the selector switch I 09 connects the non-trip-free tripping magnet 9| in the energizing circuit and disconnects the tripfree tripping magnet 19 so that operation of the fault responsive relay I03 will cause energization of only the non-trip-free magnet 9| and the breaker will be tripped only by operation of the latch 59 leaving the breaker operatively connected to the closing means.- The breaker can, therefore, be quickly reclo'sed by initiating the re closing movement before the circuit breaker reaches full open position.

When fluid pressure is admitted to the cylinder II for closing or reclosing the breaker, the pressure is also admitted through the passage I39 causing'the piston I35 to move upwardly to pen the contacts III and close the contacts H3. The trip selector switch remains in this position as long as sufficient fluid pressure remains in the cylinder II to overcome the force of the spring I. In this position the selector switch I99 connects the trip-freetripping magnet in the energizing circuit and disconnects the non-trip-free tripping magnet 9| therefrom. Consequently, if a fault condition in the main circuit occurs when the closing means is in energized condition, the fault responsive relay I03 will effect energization of the trip-free magnet 19, and the circuit breaker will betripped free of the operating piston and will be moved quickly to open position irrespective of the energized condition of the closing means.

If an overload or fault condition occurs when the mechanism is in deenergized condition, the fault responsive relay I03 will close its contacts I21 and complete an energizing circuit for the non-trip-free tripping magnet 9|. This circuit extends from the supply line I01, contacts I21 of the fault relay, conductor I25, back contacts I I I of the trip selector switch I99, conductor I23, winding 95 of the non-trip-free tripping magnet 9|, conductor H1 through auxiliary contacts 9 toithe supply line I05. Energization of the tripping magnet 9| moves the rod 99 upwardly to actuate the latch 59 to released position, thereby releasing the connected left-hand ends of the closing lever 2| and the breaker lever 23. The circuit breaker is moved quickly toward open position by the accelerating spring 53 rotating the lovers 2| and 23 clockwise about the axis 21.

Quick automatic reclosing operation of the circuit breaker is initiated before the breaker reaches full open position by admitting fluid pressure to the operating cylinder II at an intermediate point in the opening movement of the piston I5. The fluid pressure quickly reverses the direction of movement of the piston I5 and starts the reclosing movement by rotating the levers 2| and 23 counterclockwise about the axis 21. If the fault condition has been cleared by interruption of the circuit, the closing means returns the circuit breaker to the fully closed position and the latch 59 reengages the roller 63.

If the overload or fault condition is still present at the time the circuit breaker reclose's, the fault responsive relay I03 will again function to close its contacts I21. Since at this time the closing pressure is still in the cylinder II, and the trip selector switch I09 is in its upper position, the trip-free tripping magnet 19 will be immediately energized causing the rod 81 to actuate the tripfree latch 55 to unlatching position. The circuit breaker will then be moved quickly to its open position free of the operating piston. The operating piston I5 moves to its closed position at which time the supply of fluid pressure is cut oil by the inlet valve 13 and the fluid pressure above the operating piston is exhausted to atmosphere through the exhaust port of the inlet valve.

During the opening movement of the breaker lever 23, the projection 61 engages and operates the non-trip-free latch 59 to unlatching position releasing the free end of the closing lever 2| whereupon the retrieving springs 55 move the lever ZI clockwise about the axis 21. This movement of the closing lever returns the breaker lever 23 about the pivot 5| to its latched position. The two levers 2| and 23 are now operatively connected together and are in the full open position so that the mechanism is operative to close the breaker when the closing means is energized.

Referring to Fig. 2 which diagrammatically shows the circuits for controlling the inlet valve electromagnet 15 and the tripping electromagnets 19 and 9|, the winding of the electromagnet 15 which controls the admission of fluid pressure to the operating cylinder II- for closing the circuit breaker is connected in an energizing circuit extending from the supply line I05 through a conductor I43, contacts I45 of a release relay I41, the winding of the valve magnet 15, conductor I49, through contacts I5| of a closing relay I53 to the supply line I01. The energizing winding of the closing relay I53 is connected in an energizing circuit extending from the supply line I05, a conductor I55, back contacts I51 of the release relay I41, the winding of the closing relay I53, a conductor I59 and through the contacts of a manual closing switch |3I to the supply line I01. The winding of the release relay I41 is connected in an energizing circuit extending from the supply line I05, a conductor IEI, auxiliary contacts I '33 on the breaker operating mechanism adapted to be closed when the breaker reaches closed position, conductor IE5, the winding of the release relay I41, conductor I61, contacts I35 of the clos- '7 ing relay I53 and through a conductor ill to the supply line IIBI.

A stick circuit is provided for maintaining the closing relay I53 energized following a momentary operation of the manual control switch I3 I. This circuit extends from the supply line through the conductor I55, contacts I? of the release relay I43, winding of the closing relay I53, a conductor I13, contacts I99 of the closing relay I53 and conductor I'II to the supply line I97. A stick circuit is also provided for maintaining the release relay [4! energized until the manual closing switch I3I is released. This holding circuit extends from the supply line I95, a conductor IIl, contacts I79 of the release relay Ml, coil of the release relay I47, conductors I97, I13 and I59, and the manual control switch I3I to the supply conductor I91.

Heretofore, circuit breakers have been adapted to be automatically reclosed following an interruption of the circuit, through the agency of a reclosing relay which eifected energization of the closing relay. Hence, it was necessary to wait for two relays, the reclosing relay and the closing relay to pick up before the valve magnet was energized to initiate the closing operation.

According to the present invention the time required to automatically reclose the circuit breaker is materially decreased by the provision of means for effecting energization of the inlet valve magnet I5 early in the opening movement of the breaker mechanism. This means comprises a circuit controlled by normally open contacts I95 which close early in the opening operation, at least by the time the breaker contacts 3I iI have separated far enough to interrupt the circuit, independently of the closing relay. This materially decreases the time required to automatically reclose the breaker by at least the time required for the automatic reclosing relay and the closing relay to pick up. The circuit for energizing the inlet valve magnet !5 simultaneously with but independently of the closing relay I53 extends from the supply line I9! over a manual switch I85, through a lookout device I85, a conductor I93, sliding auxiliary contacts I95, a conductor I 39, winding of the valve magnet I5, contacts I95 of the release relay I4! and the conductor I93 to the supply line I95. Accordingly, the valve magnet I5 will be energized over the circuit just described as soon as the breaker mechanism has moved far enough in opening direction to close the auxiliary contacts I95 and without waiting for an automatic relay to pick up to energize the closing relay I53 and without waiting for the closing relay I53 to pick up. Thus by energizing the inlet valve magnet I5 early in the opening movement of the breaker simultaneous with but independently of the closing relay I53, the time required to automatically reclose the breaker is materially reduced.

The lockout device 28*! is of any suitable design which, after the breaker has been standing in the closed position for a predetermined time automatically prepares the circuit for energizing the inlet valve magnet and which prevents more than one quick automatic reclosing operation of the circuit breaker or opens the quick reclosing circuit and transfers the control to a time delay reclosing device in a well-known manner.

Assuming the breaker to be in the closed position, the operation of the mechanism is as follows: Upon the occurrence of a fault condition, the fault relay I93 is energized and immediately closes its contacts I27 thereby eifecting tripping of the breaker over the back contacts I II of the trip selector switch I09 and the non-trip-free tripping magnet 9I. This causes the latch 59 to release the left-hand ends of the breaker lever 23 and the closing lever 2I which rotate in opening direction about the axis 21. The breaker moves toward open position operatively connected to the piston I5. Early in the opening movement of the mechanism the contacts I close energizing the inlet valve magnet I5 and the closing relay I53 over the previously described circuit including the auxiliary contacts I95. Energization of the valve magnet I5 opens the inlet valve 73 and admits a closing charge of fluid pressure to the cylinder II which moves the piston I5 downwardly to close the breaker.

At a predetermined time during the closing operation the contacts I95 open and the reclosing operation is thereafter under the control of the closing relay I53 which was energized simultaneously with the valve magnet during the opening operation.

Operation of the closing relay I53 closes its contacts I69 to set up its stick circuit and also energizes the release relay I41, upon closing of the' contacts I63, and efiects opening of the contacts I45 and I5! which respectively drops out the inlet valve magnet 15 and opens the circuit through the winding of the closing relay I53. Deenergization of the coil of the closing relay I53 causes opening of the contacts I69 which deenergizes the coil of the release relay I47. The parts are now in their normal condition with the circuit breaker in the closed position. If there is no fault condition on the main line when the breaker is closed, the mechanism will be relatched and the breaker retained in the closed position.

If the circuit breaker closes against a fault condition, it will immediately be tripped open by the trip-free trip device since at this time the high pressure closing charge of fluid pressure is present in the operating cylinder I I and the trip selector switch I09 is in the upper position closing the contacts I I3 for energizing the trip-free tripping coil 83. Under this condition the breaker will go to the full open position free of the operating mechanism, during which movement the auxiliary contacts I95 will close but, as previously described, the lockout device I81 permits one quick reclosure and then locks the breaker out by opening the circuit through the coil of the inlet valve magnet I5 and the closing relay I53, hence, the breaker will go to its full open position. The retrieving springs 65 (Fig. 1) will function in the previously described manner to reset and relatch the mechanism so that the breaker will be connected to the piston I5 in readiness for a closing operation which may then be initiated by operation of the manual closing switch I3I to efiect energization of the closing relay I53.

It will thus be seen that there is provided a circuit breaker embodying means for quickly effecting energization of the breaker reclosing means following the initiation of an initial opening operation to materially reduce the reclosing time.

While the invention has been disclosed in accordance with the provisions of the patent statutes, it is to be understood that various changes in the structural details and arrangement of parts thereof may be made without departing from some of the essential features of the invention.

We claim as our invention:

1. An automatic reclosing circuit breaker including a control circuit, power operated means for closing said breaker, electroresponsive means for effecting energization of said power operated means. a closing relay having a coil connected in said control circuit, manually operated switch means for effecting energization of said closint rel y coil, contact means closed upon energization of said closing relay coil to effect energization of said electroresponsive means, and normally open auxiliary contact means closed upon opening movement of said circuit breaker for automatically effecting energization of said electroresponsive means simultaneously with energization of said closing relay coil to thereby reduce the time required to automatically reclose said circuit breaker.

2. An automatic reclosing circuit breaker including a control circuit, power operated means for closing said circuit breaker, electroresponsive means for effecting energization of said power operated means, a closing relay having an energizing coil connected in said control circuit, contact means operated to closed osition upon energization of said closing relay coil to effect energization of said electroresponsive means, a manual switch for effecting energization of said closing relay coil to effect energization of said electroresponsive means and closure of said breaker, and auxiliary contact means closed during an opening movement of said breaker at least by the time the breaker has opened far enough to interrupt the circuit to effect energization of said i:

electroresponsive means simultaneously with the energization of said closing relay coil to initiate a quick automatic reclosing operation before the breaker reaches full open position.

3. A circuit breaker comprising power operated means for operating said breaker to the closed position, a control circuit, trip-free tripping means including a, trip coil connected in said control circuit and operable when energized to efiect opening of said breaker irrespective of the energized condition of said closing means, non-trip-free tripping means including a. trip coil connected in said circuit and operable to effect opening of said breaker only when said closing means is in deenergized condition, electroresponsive means operable when energized to effect energization of said closing means, a closing relay having a coil connected in said circuit and having contact closed upon energization of said closing relay coil to effect energization of said electroresponsive means, a manual switch for effecting energization of said closing relay coil, auxiliary contact means closed upon opening movement of said circuit breaker to effect simultaneous energization of said closing relay coil and said electroresponsive means to thereby initiate a quick automatic reclosing operation independently of the contacts of said closing relay.

4. A circuit breaker comprising power operated means for operating said breaker to the closed position, a control circuit, trip-free tripping means including a trip coil connected in said control circuit and operable when energized to eiTect opening of said breaker irrespective of the energized condition of said closing means, nontrip-free tripping means including a trip coil connected in said circuit and operable to effect opening of said breaker only when said closing means is in deenergized condition, electroresponsive means operable when energized to effect energization of said closing means, closing relay having a, coil connected in said circuit and having contact closed upon energization of said closing relay coil to effect energization of said electroresponsive means, a manual switch for effecting energization of said closing relay coil, auxiliary contact means closed upon opening movement of said circuit breaker to effect simultaneous energization of said closing relay coil and said electroresponsive means to thereby initiate a quick automatic reclosing operation independently of the contacts of said closing relay, and means for reventing energization of said electroresponsive means in response to closure of said auxiliary contacts following a single automatic reclosing operation.

5. A circuit breaker comprising power operated means for operating said breaker to closed position, a control circuit, trip-free tripping means including a trip coil connected in control circuit and operable when energized to effect opening of said breaker free of said closing means, non-tripfree tripping means including a trip coil connected in said circuit and operable when energized to effect opening of said breaker with corresponding movement of said closing means only when said closing means is in deenergized condition, electroresponsive means operable when energized to effect energization of said closing means, a closing relay having an energizing coil connected in said circuit and having contacts closed upon energization of said closing relay coil to effect energization of said electroresponsive means, a manual switch for effecting energization of said closing relay coil to thereby initiate manual closing of said breaker, a shunt circuit connected in shunt relation with the contacts of said closing relay for effecting energization of said electroresponsive means independently of said manual switch, auxiliary contacts in said shunt circuit closed upon opening movement of said breaker to initiate a quick automatic reclosing operation, means connected in said shunt circuit permitting energization of said electroresponsive means over said shunt circuit only when said breaker is tripped by said non-tripfree tripping means, and a selector switch operated in response to the energized condition of said closing means to select the non-trip-free trip coil or the trip-free trip coil for energization.

RALPH O. BONINE. SAMUEL H. BODEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,296,300 Thumim Sept. 22, 1942 2,319,645 Thumim May 18, 1943 2,403,055 Cunningham July 2, 1946 2,408,199 Cumming et al. Sept. 24, 1946 2,422,562 Peek June 17, 1947 2,479,315 Coggeshall Aug. 16, 1949 

